It is well known that the parking brake of a motor vehicle is not always able to prevent the vehicle from moving when the parking brake is applied. A vehicle might, and can continue to roll after the parking brake is engaged if the transmission is left in its drive range and if for instance the parking brakes are worn, the engine idle speed is too high or the vehicle is on an incline. Unwanted vehicle movement after a parking brake is engaged is referred to herein as “roll-off” A method and apparatus for preventing it or protecting against it would be an improvement over the prior art.